1. Field of the Invention
The present invention relates generally to a lock closure for articles having two integral but separable parts such as portable bags, handbags, etc., and more particularly to such lock closure using magnetic attraction for coupling those two parts together.
2. Description of the Prior Art
There are various types and kinds of magnetic lock closure devices that use the attraction of a magnet, thereby keeping the articles such as handbags or coats in their closed conditions.
Those magnetic lock closure devices have different constructions depending upon their particular usages. Among others, one typical construction which is well known includes an annular permanent magnet having a central bore through it. Another typical construction includes a disk-like permanent magnet. The annular permanent magnet provides its lines of magnetic force or magnetic flux centered through the bore. The other disk-like permanent magnet provides its lines of magnetic force or magnet flux centered on one side thereof. In either case, it is known that a strong locking or coupling action can be obtained. Thus, they are used in a number of applications. For example, they are shown and described in Japanese design patent No. 5110639.
The prior art constructions that have been mentioned above are designed to provide their centered lines of magnetic force or magnetic flux consist of one part formed by a permanent magnet and which provides the attractive force and the other part usually formed by any suitable magnetically attracted material such as soft iron and which is attracted by the permanent magnet and is removably attached to the magnet. In those applications in which this type of construction is used with an article such as a bag and the like, the one part formed by the permanent magnet is usually rigidly mounted to one part of such article such as its body while the other part formed by the soft iron is usually rigidly mounted to the counterpart of the article such as a flap.
More specifically and typically, the attracting part of the above construction includes a disk-like plate of ferromagnetic material and an annular permanent magnet mounted on the disk-like plate. The disk-like plate and permanent magnet are combined together into a single unit, which is completely enclosed with a nonmagnetic cover. That is, the inner peripheral, upper surface and outer peripheral portions of the permanent magnet are totally covered. The ferromagnetic disk-like plate has a rod at its center which extends upwardly into the central bore through the permanent magnet until it reaches half way up the central bore. The rod is made of a ferromagnetic material. As such, the lines of magnetic force from one pole or N pole of the permanent magnet can enter the rod which contacts that pole, and the most part of the lines of magnetic force or magnetic flux will be centered on the rod, flowing through it toward the side of the opposite polarity or S pole of the magnet. The magnetically-attracted part of the construction consists of a similar disk-like plate of ferromagnetic material which engages the other side or S-pole side of the permanent magnet. The disk-like plate also has a rod at its center which extends upwardly into the central bore through the permanent magnet until it reaches half way and abuts against the first-mentioned rod on the side of the permanent magnet. Thus, the most part of the magnetic flux is also centered on the second-mentioned rod.
When the conventional magnetic lock closure device is used in those or other applications, there is often a problem that may occur when the two parts of the device are to be coupled together. When the part of the device that is magnetically attracted by the other part is to be attached to the other part, an attempt is usually or always made to search for the central bore of the permanent magnet so that the rod on the attracted part can register with the central bore. This attempt is usually made by blind touch rather than visually, and is accompanied by causing that rod to slide on and about the nonmagnetic cover until the central bore can be located. Sometimes, several such attempts may be made until the rod can be aligned with and engage the central bore successfully. During this sliding motion, the rod is receiving the magnetic attraction of the permanent magnet as well as a small amount of magnetic attraction by the cover even if it is nonmagnetic. Thus, the rod is attracted toward the surface of the cover during the sliding motion, which may cause scratches on the surface. Those scratches will increase as more such attempts are made. For example, articles such as bags, etc. carrying the devices are presented on display at a shop, and prospective customers usually try to check to see if a particular article will meet their respective needs. In determining an article of their choice, then, they usually attempt to see how well the device can work. In so doing, scratches may occur as described above, and the article will lose its commercial value. More opportunities of causing such scratches may occur as more prospective customers are involved.
Each of the attracting part and attracted part of the device has a fastening part formed like a pair of legs which allows the respective part to be fixed to the corresponding part of the bag, such as the body or flap. The use of this fastening part makes the portion of the body or flap where it is mounted thicker. For the flap, which is visible from the outside, the appearance or outlook of the article as a whole may be affected by the presence of the thicker portion.